Hydraulic hammer

Abstract

The present invention is a self-contained hydraulic hammer which is mounted on a hydraulically mobile frame. The hydraulic hammer is capable of travelling in either forward or reverse directions and is provided with liftable weights to which a tool for digging or breaking up a surface is attached. The hydraulic hammer is equipped with time delay controls which: 1) momentarily stop the travel of the hydraulic hammer as the weights and the attached digging tool free fall from a raised position until the digging tool impacts the surface to be busted up, and 2) cause the hydraulic hammer to resume travel as the weights are again raised in preparation for another impact. The hydraulic hammer rapidly repeats these cycles of impact and travel to break up a surface. Adjustments are provided on the hydraulic hammer for regulating the force of the impact and the distance travelled between impacts in order to match the hydraulic hammer's impact and travel cycles to the break characteristics of the surface to be removed.

What is claimed is: 
     
       1. A hydraulic hammer for breaking up a surface comprising: weights movably attached to hydraulic lifting means provided on the hydraulic hammer, a digging tool attached to the weights so that the digging tool impacts the surface when the weights fall from a lifted position,   a limit switch located on the hydraulic hammer so the limit switch is tripped by the weights at their lifted position, said limit switch being electrically connected to a pair of delay timers, one said delay timer being electrically connected to a weight control means and the other said delay timer being connected to a drive control means, said weight control means connected to the hydraulic lifting means in order to control lifting and falling of the weights from their lifted position, said drive control means being connected to hydraulic drive means provided on the hydraulic hammer in order to control travel of the hydraulic hammer along the surface; and   said delay timers being synchronized so the hydraulic hammer travels as the weights are lifted and so the hydraulic hammer stops travelling as the weights fall.   
     
     
       2. A hydraulic hammer according to claim 1 wherein the lifting means comprises: a weight lifting cylinder provided on a frame of the hydraulic hammer, said weight lifting cylinder being provided with a hydraulically movable piston, said weight lifting cylinder being hydraulically connected to the weight control means, a first set of sheaves attached to an upper end of the piston, a second set of sheaves attached to the frame, a cable having first and second ends, said cable being attached on its first end to the frame and engaging the second and first set of sheaves in back-and-forth fashion before extending over a lifting sheave provided above the weights on the hydraulic hammer, and said second end extending downward from the lifting sheave and attached to the weights so that the weights are lifted when the piston moves away from the weight lifting cylinder, and dump valve means for quickly moving the piston toward the weight lifting cylinder in order to cause the weights to fall toward the surface.   
     
     
       3. A hydraulic hammer according to claim 2 wherein the weight control means comprises: a cylinder solenoid being hydraulically connected to the weight lifting cylinder in order to move the piston away from the weight lifting cylinder, and   a dump valve solenoid being hydraulically connected to the dump valve means in order to move the piston toward the weight lifting cylinder.   
     
     
       4. A hydraulic hammer according to claim 1 wherein the drive means comprises: drive wheels being rotatably attached one on each side of a frame of the hydraulic hammer, said drive wheels being rotated by at least one hydraulic drive motor; and each said at least one hydraulic drive motor hydraulically attached to the drive control means.   
     
     
       5. A hydraulic hammer according to claim 4 wherein the drive control means comprises: a forward drive solenoid being hydraulically connected to each said at least one hydraulic motor in order to rotate the drive wheels so the hydraulic hammer moves in a forward direction, and   a reverse drive solenoid being hydraulically connected to each said at least one hydraulic drive motor in order to rotate the drive wheels so the hydraulic hammer moves in a reverse direction.   
     
     
       6. A hydraulic hammer for breaking up a surface comprising: weights movably provided on the hydraulic hammer, said weights being movable to a lifted position by hydraulic lifting means attached to the weights,   a circuit breaking means provided on the hydraulic hammer so that the weights trip the circuit breaking means when the weights are raised to their lifted position,   drive control means and weight control means being electrically connected to the circuit breaker means so that the drive control means and the weight control means are simultaneously deactivated when the circuit breaker means is tripped;   said drive control means being hydraulically connected to drive means for moving the hydraulic hammer, said weight control means being hydraulically connected to the hydraulic lifting means in order to raise the weight, a digging tool provided on the weights so that the digging tool impacts the surface when the weights fall,   one delay timer being electrically connected to the circuit breaker means and to the drive control means, a second delay timer being electrically connected to the circuit breaker means and to the weight control means, and said delay timers being synchronized so they simultaneously reconnect power to the weight control means and the drive control means.